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Search Results: 1 - 10 of 219578 matches for " C. Vitelli "
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Adolescências e identidades estéticas no cotidiano
Vitelli, Celso;
Educa??o em Revista , 2009, DOI: 10.1590/S0102-46982009000300004
Abstract: this article deals with the contemporary transformations that have put forward different views of important concepts, of which we highlight those of culture, consumption, esthetics, adolescence and art. these concepts, related to one another, have been approached having the adolescent as the center of the discussion. the study attempts to bring the quotidian of the adolescent to the center of the scene, valuing every action and speech as a means to enable the investigation of adolescence, whereas considering the speed of the changes that mark the present time and space. the investigation has unveiled a quotidian in which adolescence is celebrated in our culture, at the same time influenced by a society strongly directed towards consumption, interfering in the conception of social and cultural values constantly produced and reproduced.
Representa??es das masculinidades hegemónicas e subalternas no cinema
Análise Social , 2011,
Abstract: this article discusses part of the theory proposed by robert connell regarding masculinity as portrayed in the film crash, by paul haggis. we analyze two forms of masculinity in the film (hegemonic and subaltern) and their relationships to power, including the culture of the image, specifically, the language of film.
Representa es das masculinidades hegemónicas e subalternas no cinema Representations of masculine hegemony and subalterns in the cinema
Celso Vitelli
Análise Social , 2011,
Abstract: Este artigo discute parte da teoria proposta por Robert Connell sobre masculinidades, relacionando-a com situa es do filme Crash, de Paul Haggis. Analisam-se as diferentes masculinidades apresentadas no filme (hegemónica e subalterna) e as suas rela es com o poder, incluindo a cultura da imagem, especificamente na linguagem do cinema. This article discusses part of the theory proposed by Robert Connell regarding masculinity as portrayed in the film Crash, by Paul Haggis. We analyze two forms of masculinity in the film (hegemonic and subaltern) and their relationships to power, including the culture of the image, specifically, the language of film.
Attenuation of shear sound waves in jammed solids
Vincenzo Vitelli
Physics , 2010,
Abstract: We study the attenuation of long-wavelength shear sound waves propagating through model jammed packings of frictionless soft spheres interacting with repulsive springs. The elastic attenuation coefficient, $\alpha(\omega)$, of transverse phonons of low frequency, $\omega$, exhibits power law scaling as the packing fraction $\phi$ is lowered towards $\phi_c$, the critical packing fraction below which rigidity is lost. The elastic attenuation coefficient is inversely proportional to the scattering mean free path and follows Rayleigh law with $\alpha(\omega)\sim \omega^4 (\phi - \phi_c)^{-5/2}$ for $\omega$ much less than $\omega^* \sim (\phi - \phi_c)^{1/2}$, the characteristic frequency scale above which the energy diffusivity and density of states plateau. This scaling of the attenuation coefficient, consistent with numerics, is obtained by assuming that a jammed packing can be viewed as a mosaic composed of domains whose characteristic size $\ell^ * \sim (\phi-\phi_c) ^{-1/2}$ diverges at the transition.
Extrinsic Curvature, Geometric Optics, and Lamellar Order on Curved Substrates
R. D. Kamien,D. R. Nelson,C. D. Santangelo,V. Vitelli
Physics , 2009, DOI: 10.1103/PhysRevE.80.051703
Abstract: When thermal energies are weak, two dimensional lamellar structures confined on a curved substrate display complex patterns arising from the competition between layer bending and compression in the presence of geometric constraints. We present broad design principles to engineer the geometry of the underlying substrate so that a desired lamellar pattern can be obtained by self-assembly. Two distinct physical effects are identified as key factors that contribute to the interaction between the shape of the underlying surface and the resulting lamellar morphology. The first is a local ordering field for the direction of each individual layer which tends to minimize its curvature with respect to the three-dimensional embedding. The second is a non-local effect controlled by the intrinsic geometry of the surface that forces the normals to the (nearly incompressible) layers to lie on geodesics, leading to caustic formation as in optics. As a result, different surface morphologies with predominantly positive or negative Gaussian curvature can act as converging or diverging lenses respectively. By combining these ingredients, as one would with different optical elements, complex lamellar morphologies can be obtained. This smectic optometry enables the manipulation of lamellar configurations for the design of novel materials.
Quantum to classical transition via fuzzy measurements on high gain spontaneous parametric down-conversion
C. Vitelli,N. Spagnolo,L. Toffoli,F. Sciarrino,F. De Martini
Physics , 2010, DOI: 10.1103/PhysRevA.81.032123
Abstract: We consider the high gain spontaneous parametric down-conversion in a non collinear geometry as a paradigmatic scenario to investigate the quantum-to-classical transition by increasing the pump power, that is, the average number of generated photons. The possibility of observing quantum correlations in such macroscopic quantum system through dichotomic measurement will be analyzed by addressing two different measurement schemes, based on different dichotomization processes. More specifically, we will investigate the persistence of non-locality in an increasing size n/2-spin singlet state by studying the change in the correlations form as $n$ increases, both in the ideal case and in presence of losses. We observe a fast decrease in the amount of Bell's inequality violation for increasing system size. This theoretical analysis is supported by the experimental observation of macro-macro correlations with an average number of photons of about 10^3. Our results enlighten the practical extreme difficulty of observing non-locality by performing such a dichotomic fuzzy measurement.
Enhanced Resolution of Lossy Interferometry by Coherent Amplification of Single Photons
C. Vitelli,N. Spagnolo,L. Toffoli,F. Sciarrino,F. De Martini
Physics , 2010, DOI: 10.1103/PhysRevLett.105.113602
Abstract: In the quantum sensing context most of the efforts to design novel quantum techniques of sensing have been constrained to idealized, noise-free scenarios, in which effects of environmental disturbances could be neglected. In this work, we propose to exploit optical parametric amplification to boost interferometry sensitivity in the presence of losses in a minimally invasive scenario. By performing the amplification process on the microscopic probe after the interaction with the sample, we can beat the losses detrimental effect on the phase measurement which affects the single-photon state after its interaction with the sample, and thus improve the achievable sensitivity.
Saddle-splay screening and chiral symmetry breaking in toroidal nematics
Vinzenz Koning,Benjamin C. van Zuiden,Randall D. Kamien,Vincenzo Vitelli
Physics , 2013,
Abstract: We present a theoretical study of director fields in toroidal geometries with degenerate planar boundary conditions. We find spontaneous chirality: despite the achiral nature of nematics the director configuration show a handedness if the toroid is thick enough. In the chiral state the director field displays a double twist, whereas in the achiral state there is only bend deformation. The critical thickness increases as the difference between the twist and saddle-splay moduli grows. A positive saddle-splay modulus prefers alignment along the short circle of the bounding torus, and hence stimulates promotes a chiral configuration. The chiral-achiral transition mimics the order-disorder transition of the mean-field Ising model. The role of the magnetisation in the Ising model is played by the degree of twist. The role of the temperature is played by the aspect ratio of the torus. Remarkably, an external field does not break the chiral symmetry explicitly, but shifts the transition. In the case of toroidal cholesterics, we do find a preference for one chirality over the other -- the molecular chirality acts as a field in the Ising analogy.
Quantum interferometry with three-dimensional geometry
N. Spagnolo,L. Aparo,C. Vitelli,A. Crespi,R. Ramponi,R. Osellame,P. Mataloni,F. Sciarrino
Physics , 2013, DOI: 10.1038/srep00862
Abstract: Quantum interferometry uses quantum resources to improve phase estimation with respect to classical methods. Here we propose and theoretically investigate a new quantum interferometric scheme based on three-dimensional waveguide devices. These can be implemented by femtosecond laser waveguide writing, recently adopted for quantum applications. In particular, multiarm interferometers include "tritter" and "quarter" as basic elements, corresponding to the generalization of a beam splitter to a 3- and 4-port splitter, respectively. By injecting Fock states in the input ports of such interferometers, fringe patterns characterized by nonclassical visibilities are expected. This enables outperforming the quantum Fisher information obtained with classical fields in phase estimation. We also discuss the possibility of achieving the simultaneous estimation of more than one optical phase. This approach is expected to open new perspectives to quantum enhanced sensing and metrology performed in integrated photonic.
Mechanical Weyl Modes in Topological Maxwell Lattices
D. Zeb Rocklin,Bryan Gin-ge Chen,Martin Falk,Vincenzo Vitelli,T. C. Lubensky
Physics , 2015,
Abstract: Topological mechanical structures exhibit robust properties protected by topological invariants. In this letter, we study a family of deformed square lattices that display topologically protected zero-energy bulk modes analogous to the massless fermion modes of Weyl semimetals. Our findings apply to sufficiently complex lattices satisfying the Maxwell criterion of equal numbers of constraints and degrees of freedom. We demonstrate that such systems exhibit pairs of oppositely charged Weyl points, corresponding to zero-frequency bulk modes, that can appear at the origin of the Brillouin zone and move away to the zone edge (or return to the origin) where they annihilate. We prove that the existence of these Weyl points leads to a wavenumber-dependent count of topological mechanical states at free surfaces and domain walls.
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